Nick Ling: Waikato University Ecology Expert on the danger to marine life after the Manawanui sunk by Samoa

The marine life around Samoa is likely in danger in the wake of Manawanui sinking. 

The $100 million naval ship struck a reef off the south coast of Upolu on Saturday, before sinking Sunday morning.  

About 950 tonnes of oil is onboard.  

Diesel leaked out of the vessel when it capsized and has coated the surface of the water.  

Waikato University ecology expert Nick Ling told Ryan Bridge much of the material released would have evaporated, leaving behind these heavier components we can see.  

He says marine animals interacting with the surface —like turtles coming to the surface to breathe— will have to interact with it. 

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Episode Transcript

Speaker 1 (00:00):
The potential echo catastrophe the Mono Manui. This is in Samaira.
Videos captured near the site yesterday of the grounding showing
a turtle struggling to swim in a thick oil slick
with shipping containers, planks of wood and life jackets floating nearby.
Nick Ling is the associate professor at Warcuter University School
of Medicine. He's with us this morning, Nick, Good.

Speaker 2 (00:20):
Morning, Yeah, good morning, right, how are you?

Speaker 1 (00:23):
Yeah, I'm good, thank you. So this oil, let's first
of all, there's a thousand tons of it. This is
not Arina grade heavy oil. This is engine oil.

Speaker 2 (00:35):
Yeah, so as I understand it, unlike the fuel oil
that was on the arena, which was called heavy fuel oil,
this is a much lighter grade. So it's more similar
to automotive diesel oil. So the thing is with these
ship oils is that they contain a mixture of different hydrocarbons.
And obviously the stuff that we burn in our cars

(00:57):
is a very light grade. And so if you leave
that too, if you have the spill of that, it
would just simply evaporate away. So the stuff that's on
the Manuwanui is a light grade of shipping fuel oil,
and so much of the material that was released in
the early spill would have evaporated off and that leaves

(01:17):
a residue of the sort of heavier components, and that's
what would have been observed yesterday in the video of
that struggling turtle. And obviously, you know those sort of
marine animals, anything that has to interact with the surface,
like those turtles that have to come to the surface
to breathe, they will then encounter that.

Speaker 1 (01:37):
And the case that stays on the surface, does it.

Speaker 2 (01:43):
Yeah, yeah, Well, as the spill progresses, much of those
lighter components will evaporate and then finally the last stage
is that you'll get sort of tari deposits which will
actually be heavier than the water, and they will then
finally sink as tar balls to the bottom.

Speaker 1 (01:59):
Right, And how big is this? How big of a
deal is this a thousand tons?

Speaker 2 (02:05):
It's certainly pretty big. So that's about three times the
amount of oil that was released from Marena wreck. But
certainly the media reports yesterday of the first assessment of
the wreck by divers are very encouraging in that they're
not showing any leakage currently and that would suggest that
almost all of that is contained within the wreck. So

(02:27):
obviously the next priority would be to remove that material
through salvaging the wreck.

Speaker 1 (02:35):
Right, is there a risk actually getting SALVO vessels in
there that we might have a pile up?

Speaker 2 (02:41):
Yeah, well certainly. You know, obviously it's right next to
a reef and it's a fairly exposed place, so there
is the potential hazard of working in that area when
you're sending other marine assets into that area. But it's
not impossible to do that obviously. The experts salvas are

(03:03):
used to working in those sort of conditions. I mean
that was the case with the Arena as well. The
salvers had to work right next to the reef in
a very exposed area, and so it's just a case
of managing that risk.

Speaker 1 (03:13):
So best case scenario here, Nick, we have most of
the oil apparently still contained within the vessel. If we
can get in there Selvo, the environmental impact might be
quite small.

Speaker 2 (03:26):
Yeah, yeah, potentially, Yeah, I mean obviously there's potentially other
things on the wreck as well. I mean that was
the case with the Arena. You know, it had contained
as a dangerous goods on board. We don't know what
else is on the Manawanui at this stage, you know,
potentially there's munitions and those sort of things that might
be on a naval ship and they would need to
be salvage as well. But certainly the initial assessment seems

(03:47):
very encouraging that the wreck is fully intact, that's sitting
on the bottom at a reasonable depth. It's only thirty
meters deep. That means it's accessible by normal divers. The
fact that it's intact means that removing the oil should
be a much more simple task, and potentially salvaging the

(04:08):
entire wreck and removing it entirely is obviously easier to
do when the reck is intact rather than broken up.

Speaker 1 (04:15):
Yeah, well that's a good point, and it's only thirty
meters deep, so that is potentially a possibility. Nick, Thank
you so much for your time. Nick Ling, Associate Professor,
School of Science at why katz A University, saying that
scigns are looking good in terms of the environmental impact.
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